Alert archive / North Dakota / Tornado Watches in 2011
Tornado Watch 644
The Storm Prediction Center issued this tornado watch at Jul 14, 2011, 4:33 PM MDT for 16 counties in North Dakota; 11 counties in South Dakota. It was in force for 7 hr.
The area
The outline as issued.
The facts
- Issued
- Jul 14, 2011, 4:33 PM MDT (22:33 UTC)
- Expired
- Jul 15, 2011, 12:00 AM MDT
- In force
- 7 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 3 in
- Strongest gust expected
- 60 kt
All 27 counties
Adams County, ND, Billings County, ND, Bowman County, ND, Burleigh County, ND, Emmons County, ND, Golden Valley County, ND, Grant County, ND, Hettinger County, ND, Kidder County, ND, Logan County, ND, McIntosh County, ND, Morton County, ND, Oliver County, ND, Sioux County, ND, Slope County, ND, Stark County, ND, Campbell County, SD, Corson County, SD, Dewey County, SD, Edmunds County, SD, Faulk County, SD, Harding County, SD, McPherson County, SD, Perkins County, SD, Potter County, SD, Walworth County, SD, Ziebach County, SD
The radar
The Bismarck radar (KBIS), 114 km from the middle of the area, began a volume at 22:33 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
What SPC expected
The probabilities SPC published with the watch, for the watch area over its life.
- Two or more tornadoes
- 50%
- One or more EF2 to EF5 tornadoes
- 20%
- Ten or more severe wind reports
- 60%
- One or more gusts of 65 knots or more
- 30%
- Ten or more severe hail reports
- 90%
- One or more hailstones of 2 inches or more
- 60%
- Six or more combined severe hail and wind reports
- 95%
Warnings issued inside it
11 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 14, 5:08 PM MDT | Severe Thunderstorm Warning | UNR | Harding, Perkins | 50 min |
| Jul 14, 5:18 PM MDT | Severe Thunderstorm Warning | UNR | Harding | 27 min |
| Jul 14, 5:51 PM MDT | Severe Thunderstorm Warning | UNR | Harding, Perkins | 54 min |
| Jul 14, 6:46 PM MDT | Severe Thunderstorm Warning | UNR | Perkins | 22 min |
| Jul 14, 7:12 PM MDT | Severe Thunderstorm Warning | UNR | Perkins | 63 min |
| Jul 14, 7:54 PM MDT | Severe Thunderstorm Warning | UNR | Perkins, Ziebach | 81 min |
| Jul 14, 8:23 PM MDT | Flash Flood Warning | UNR | Perkins | 4 hr |
| Jul 14, 8:54 PM MDT | Severe Thunderstorm Warning | ABR | Corson, Dewey | 51 min |
| Jul 14, 9:43 PM MDT | Severe Thunderstorm Warning | ABR | Corson, Dewey | 45 min |
| Jul 14, 10:42 PM MDT | Severe Thunderstorm Warning | BIS | Billings, Golden Valley, McKenzie | 63 min |
| Jul 14, 11:33 PM MDT | Severe Thunderstorm Warning | ABR | Campbell, Corson | 42 min |
Discussions around it
SPC mesoscale discussions over the same counties from four hours before the watch to its end.
The nearest sounding before it
Bismarck Municip, ND (KBIS), launched 12:00Z, 10.6 hours before the alert went out and 117 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 9 J/kg
- Mixed-layer CIN
- -181 J/kg
- Mixed-layer LCL
- 468 m above ground
- 0-6 km bulk shear
- 32 kt
- 0-1 km storm-relative helicity
- 107 m²/s²
- 0-3 km storm-relative helicity
- 174 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.3
The text
As transmitted, in the capitals the NWS used until 2016.
419
WWUS20 KWNS 142233
SEL4
SPC WW 142233
NDZ000-SDZ000-150600-
URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 644
NWS STORM PREDICTION CENTER NORMAN OK
435 PM MDT THU JUL 14 2011
THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF
SOUTHERN NORTH DAKOTA
NORTHERN SOUTH DAKOTA
EFFECTIVE THIS THURSDAY AFTERNOON FROM 435 PM UNTIL MIDNIGHT MDT.
TORNADOES...HAIL TO 3 INCHES IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.
THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 70 STATUTE
MILES NORTH AND SOUTH OF A LINE FROM 40 MILES NORTHWEST OF
BUFFALO SOUTH DAKOTA TO 85 MILES EAST NORTHEAST OF MOBRIDGE SOUTH
DAKOTA. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED
WATCH OUTLINE UPDATE (WOUS64 KWNS WOU4).
REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS.
OTHER WATCH INFORMATION...CONTINUE...WW 642...WW 643...
DISCUSSION...THUNDERSTORMS ARE EXPECTED TO RAPIDLY DEVELOP OVER
NORTHWEST ND/SOUTHWEST SD AND TRACK EASTWARD ALONG A WARM FRONT
ACROSS THE WATCH AREA THIS EVENING. VERY HIGH CAPE AND AMPLE LOW
LEVEL MOISTURE...COUPLED WITH VEERING LOW LEVEL AND MODERATELY
STRONG MID LEVEL WINDS...WILL PROMOTE A RISK OF SPLITTING SUPERCELLS
CAPABLE OF VERY LARGE HAIL AND ISOLATED TORNADOES.
AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 3 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
550. MEAN STORM MOTION VECTOR 28030.
...HARTSPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 14, 2:55 PM MDT | Mesoscale Discussion | SPC | Sioux | 2 hr |
Nearby
Tornado Watches in North Dakota, 2011Tornado Watches in South Dakota, 2011Every tornado watch in 2011
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.